Current Conversion Research Articles

Manipulation of Spin-Orbit Torque in Tungsten Oxide/Manganite Heterostructure by Ionic Liquid Gating and Orbit Engineering.

Spin-orbit coupling (SOC) is the interaction between electron's spin and orbital motion, which could realize a charge-to-spin current conversion and enable an innovative method to switch the magnetization by spin-orbit torque (SOT). Varied techniques have been developed to manipulate and improve the SOT, but the role of the orbit degree of freedom, which should have a crucial bearing on the SOC and SOT, is still confusing. Here, we find that the charge-to-spin current conversion and SOT in W3O8-δ/(La, Sr)MnO3 could be produced or eliminated by ionic liquid gating. Through tuning the preferential occupancy of Mn/W-d electrons from the in-plane (dx2-y2) to out-of-plane (d3z2-r2) orbit, the SOT damping-like field efficiency is nearly doubled due to the enhanced spin Hall effect and interfacial Rashba-Edelstein effect. These findings not only offer intriguing opportunities to control the SOT for high-efficient spintronic devices but also could be a fundamental step toward spin-orbitronics in the future.

Hierarchical electronic coupling engineering of bimetallic sulfide driven by CoFe bimetal MOFs anchored on MXene promotes efficient overall water splitting

Rational design cost-effective water-splitting catalysts are essential for current energy storage and conversion. Here, we ingeniously design alloy-phase bimetallic sulfides anchored on the conductive substrate MXene, obtained by a facile topological hydrothermal sulfide method of self-template sacrifice using bimetallic MOFs. Density functional theory calculations (DFT) and related material characterization demonstrate that electron rearrangement at the atomic/orbital level and hierarchical electronic coupling between Schottky heterostructures of MXene boosts charge transfer efficiency, the asymmetric 3d electronic structure of the Co-Fe atoms optimizes the d-band center value εd of the Co8FeS8 MXene/NF. Thus, the efficient composite electrocatalyst of Co8FeS8 MXene/NF with multi-metal active sites exhibits extraordinary electrocatalytic performance with remarkably low overpotentials of 171 mV (OER) and 108 mV (HER) at 10 mA cm−2, respectively. Notably, when used in 1 M KOH electrolytic cell, Co8FeS8 MXene/NF also accelerate overall water splitting at an ultra-low cell voltage of only 1.51 V at 10 mA cm−2, far exceeding that of standard Pt-C/NF//RuO2/NF electrodes (1.59 V). This work gives an effective strategy to construct MOF-derived alloy-phase bimetallic sulfides and improve the intrinsic activity of alloy-phase bimetallic sulfides electrochemical catalysts.

Learning From Field Testing Experiences for Developing Small Scale Tidal Current Energy Conversion System

Tidal current energy conversion system (TCECS) has been tested in potential straits such as the Larantuka Strait and Madura Strait. In its development, the technology will be improved by increasing its capacity to 100 kW. The new capacity is planned to use a farming system with vertical axis turbines. The experience of installing and operating a TCECS prototype with a capacity of 10-20 kW in Indonesia could be a valuable experience for the implementation phase of a TCECS with a higher capacity. This paper aims to report the experience of TCECS installation in Indonesia. According to previous installation experience, TCECS was made floating using a catamaran type as a supporting structure. This was done to facilitate the transportation process from the production site to the installation site. TCECS production was carried out in an area that is quite far from the installation area because there is not enough land around it to assemble or produce the technology. This condition is one of the factors that need to be considered in the TCECS installation step in Indonesia. Another factor to consider is the size of the TCECS technology to be utilized. The Installation facilities in Indonesia, especially in the eastern region, have been yet inadequate in using large equipment, e.g., a heavy crane. Therefore, the dimensions of the TCECS to be installed should not have large dimensions. To take the experience of the installation, other factors are described in several chapters in this paper.

Energy-Mass and Thermoelectric Characteristics of the Current Convertor, Made on the Devices of Plasma Electric Power Industry

In space power propulsion systems (SPPS) based on a low-voltage power source and high-voltage electric rocket thrusters, a current conversion system (CCS) is required. As one of the elements of promising high–temperature CCS, high-temperature plasma thermal emission valves (HPTV) of plasma electric power industry are considered – grid key elements (GKE) and high-voltage plasma thermal emission diodes (HVPTD). In the work, the modeling of the energy-mass characteristics of the CCS built on the GKE and HVPTD using heat pipes (HP) for cooling is carried out, the temperature conditions in which the minimum specific mass of the current converter is achieved are determined. The specific gravity values are determined. The results of the work can be used in the development of new high-temperature CCS space power propulsion systems for electrical power from tens to thousands of kilowatts.

Photoelectrocatalytic based simultaneous removal of multiple organic micro-pollutants by using a visible light driven BiVO4 photoanode

In this research, photoelectrocatalytic (PEC) based advanced oxidation process (AOP) was studied for the removal of multiple OMPs through an oxidative mechanism. This study investigated the application of a BiVO4 photoanode in simultaneous removal of three selected OMPs: acetaminophen (ACT), benzotriazole (BTA) and propranolol (PRO). This study was carried out in demineralized water with a starting concentration of each organic micro-pollutant (OMP) at 45 μg L−1. In order to fabricate BiVO4 photoanodes, a facile and effective dip-coating method was used to deposit BiVO4 photocatalytic layers on fluorine doped tin oxide (FTO) substrate. UV–vis diffusive reflectance spectroscopy, x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) confirmed the successful fabrication of porous BiVO4 photoanode having an absorbance edge at around 526 nm. The fabricated photoanode showed incident photon to current conversion efficiency (IPCE) of 9.23% (λmax=445 nm) under 1 Sun standard illumination. Application of the fabricated photoanodes for the simultaneous removal of ACT, PRO and BTA at an applied voltage of 1 V (vs Ag/AgCl) under solar simulated light resulted in 99% removal of both ACT and PRO, and 70% removal of BTA. The first order rate coefficients and half-life times of ACT and PRO were about three times higher than those of BTA.

Free‐Standing and Highly Tough 3D Network of Carbon Nanotubes and MXene Constructed by Facile “Egg‐Box” Coordination Mechanism for High‐Efficiency Solar Evaporator

Solar steam generation to generate steam through solar light‐driven surface evaporation can be an attractive methodology that utilizes green and inexhaustible solar energy to generate water steam and fresh water with superior efficiency. However, some drawbacks of the current photothermal conversion materials such as complicated fabrication process, high cost, and low salt tolerance often heavily restrict their wide applications. Herein, a green and low‐cost method is designed and developed for constructing a free‐standing, elastic, and highly tough 3D network of carbon nanotubes (CNTs) and MXene through an efficient “egg‐box” coordination mechanism in only one step for high‐efficiency water evaporation. When the mass ratios of MXene and CNTs are designed at 1:1.5 and cross‐linked with sodium alginate and CaCl2, the obtained MCS‐3 shows the most excellent light absorption and hydrophilicity, leading to the best evaporation rate of 1.644 kg m−2 h−1, and the highest photothermal conversion efficiency of 96%. Moreover, subject to different harsh environments and durability tests, MCS‐3 also shows desired structural stability and evaporation performance. As demonstrated by its extraordinary photothermal evaporation properties, MCS‐3 can envision a wide range of commercial applications covering wastewater purification, brine seawater, desalination, etc.

Environmental performance of nonthermal plasma dry and conventional steam reforming of methane for hydrogen production: Application of life cycle assessment methodology

The environmental performance of nonthermal plasma assisted dry reforming of methane (NTP-DRM) for hydrogen production from methane rich natural gas is investigated and compared with the current state of the art steam reforming technology through a cradle-to-gate life cycle assessment (LCA). The NTP-DRM technologies studied in this analysis include dielectric barrier, microwave, and pulsed plasma discharges. Due to the level of technology the study is considered as the prospective LCA of selected types of NTP-DRMs for hydrogen production. Of these, the NTP-DRM using microwave and pulsed plasma presented better environmental performance. The impact categories include midpoints levels applying TRACI 2.1 and AWARE for the water scarcity, using ecoinvent 3.8 and US NETL databases. The scenario analysis regarding carbon dioxide, electricity, and natural gas sources, revealed the highly dependency of NTP-DRMs technologies environmental performance to the energy efficiency of the processes. In terms of steam reforming of methane (SRM) despite the main contribution of steam use in the technology environmental performance, the uncertainty analysis showed higher sensitivity to natural gas input. Investigation showed that using renewable energy sources can have significant improvement regarding NTP-DRMs environmental performance and specifically global warming potential. Accordingly, at their current reactant conversion and product selectivity reaching the energy use of eV per molecule of reactant equal or less than 2, can be a proper target for the studied best case NTP-DRM to make their environmental behavior competitive with the state-of-the-art SRM technologies.

Performance analysis of PID controller and fuzzy logic controller for DC-DC boost converter.

Demand of Power electronics converter is increased due to the rapid increase of green re-sources. The distributed nature of uncontrolled renewable energy resources are connected with the grid via power electronics converter. DC-DC converters are high-frequency current conversion circuits that use transformers, inductors, and capacitors to smooth switching noise into regulated DC voltages. In this study, a comparative performance analysis of Proportional integral Derivative (PID) and fuzzy logic controller (FLC) for DC-DC Boost Converter is presented. PID-based controller for dynamic boosting of DC-DC boost converter was replaced by Fuzzy Inference system (FIS) to study the system behavior. Five different membership functions were performed to observe the response of the system for DC -DC boost converter with FIS controller. The performances of FIS-based controller and PID-based controller for DC-DC boost converter were compared in detail. Also, the proposed techniques for the switching mode of DC-DC converter have been applied. The performance analysis of both PID and fuzzy controller was simulated using MAT LAB. The results of FIS based approach are better than PID based controller in terms of transient responses.

State primary standard of units for electric current intensity conversion coeffi cients GET 152-2023

The metrological support of measuring current converters as the main elements intended for measuring a large electric current is considered. Brief historical information about the creation of the State primary standard of units for electric current intensity conversion coeffi cients is given. The composition and metrological characteristics of the State primary standard of units for electric current intensity conversion coeffi cients GET 152-2023 are presented. The equations of measurements and the results of the studies of two standard measuring installations created as part of the improvement of GET 152-2023 from 2019 to 2022 are given. It is shown that the range of reproducible rated primary currents of a sinusoidal current installation is 1–1000 A in the frequency range of 40–2500 Hz, and the range of reproducible rated primary currents of a high direct current installation is 1000–10000 A. The data on the state verifi cation scheme for measuring instruments of the electric current conversion coeffi cients are given. Comparisons with the participation of UNIIM as a pilot for the period from 2019 to the present are listed. The prospects of further improvement of the GET 152-2023 to expand the measurement and calibration capabilities of this fi eld of measurement in the Russian Federation are described. The results of the work are relevant for metrological support of measuring converters of large electric current used in power engineering and industry.

Spin-to-charge conversion origin in graphene on ferromagnetic substrate revealed: Rashba effects at Dirac point

Spin-to-charge current conversion (SCC) by inverse Rashba Edelstein effect (IREE) has been recently observed by spin-pumping experiment in single layer graphene (SLG) placed on ferromagnetic substrate composed mostly of Ni. However, a prior angle-resolved photoemission spectroscopy (ARPES) shows a negligible Rashba splitting at Γ−M, unsupportive of SCC by IREE. In this work, using density functional theory with spin-orbit coupling (DFT + SOC) calculations, we obtained the Rashba-type spin-resolved bandstructure on relevant symmetric k-points of SLG on Ni(111). We found no Rashba splitting at Γ−M confirming ARPES, however, we discovered considerable Rashba splittings in the dispersions along M−K−M, that is, involving the Dirac point, paving the way for SCC by IREE. Thus, for the first time, this work has reconciled the above seemingly contradicting spin-pumping and ARPES experiments, revealed the physical and magnetic origin of SCC by IREE and proposed means to increase the SCC coefficient without the use of heavy precious metals.

Effect of various layers on improving the photovoltaic efficiency of Al/ZnO/CdS/CdTe/Cu2O/Ni solar cells

The photovoltaic (PV) cell structure containing Al/ZnO/CdS/CdTe/Cu2O/Ni has been simulated using the SCAPS-1D software. The PV device includes a zinc oxide (ZnO) transparent conductive oxide (TCO) window layer, a cadmium sulfide (CdS) buffer layer, and a cadmium telluride (CdTe) absorber layer. Additionally, an electron reflected-hole transport layer (ER-HTL) comprising cuprous oxide (Cu2O) is introduced between the absorber layer and the back metal contact. Aluminum (Al) and nickel (Ni) serve as the upper/top and back contact materials, respectively, interconnecting the layers. The back contact materials, the thickness of the absorber, buffer, and window layers, the acceptor density of the absorber layer, the donor density of the buffer layer, the series and shunt resistance, as well as temperature, were all modified to investigate the PV performance of this structure. The PV performance parameters are evaluated through the open-circuit voltage (VOC), short-circuit current (JSC), fill factor (FF), and power conversion efficiency (PCE). To achieve optimal performance, it is recommended to set the acceptor and donor densities for the absorber and buffer layers at 1017 cm−3. These desired densities can be attained by using a window and buffer layer thickness of 100 nm, an absorber layer thickness of 2500 nm, and an ER-HTL of 50 nm. The optimized model demonstrates PV performance characteristics of 1.4811 V for VOC, 28.682434 mA/cm2 for JSC, 74.91 % for FF, and 31.82 % for PCE under the AM 1.5 G spectrum. Furthermore, it exhibits a quantum efficiency of around 100 % at visible wavelengths.

How do carbon dots with amine terminals help perovskite solar cells perform better?

Lead halide perovskite solar cells can be significantly improved with multifunctional additives such as carbon dots (CDs) with amine terminals via defect passivation and band alignment. Here, we determine rational guidelines for the usage of such quantum dots in perovskite solar cells by systematically studying their effects on crystal quality and carrier transport. The amine-terminated CDs homogeneously dispersed in precursors improve the crystal quality of perovskite films, but they reduce the hole mobility hampering hole extraction. In contrast, CDs deposited between the electron transport layer and active layer could promote spin-coated film quality and electron’s extraction efficiently. So, the approaches of the carbon dots in device alters semiconductor properties and energy level structure. Interface engineering achieve better crystal quality and energy level alignment, which in turn affects charge collection, thereby increasing current density and power conversion efficiency. According to the findings of this study, when considering defect passivation by additives, the energy band alignment of the device should also be considered, since this could change carrier dynamics and device performance differently.

Gain-enhanced triple-band rectifier-integrated antenna for microwave wireless power transmission

Abstract This paper proposes a triple-band fractal slot antenna with enhanced gain operating at frequencies of 2.7, 3.5, and 4.8 GHz for microwave wireless power transmission. The antenna achieved more than 3 dB gain by preserving the symmetrical defected reflector structure behind it at a length of 0.54λ/4, where λ is the wavelength in free space at 2.7 GHz. A 50 Ω micro-strip line coupled at 66 mm length helps feed the triple band slot antenna. The purpose of a triple-band rectifier circuit with an impedance network is to convert the radio frequency (RF) signal into direct current. The measurements reveal that the antenna’s enhanced gain is 8.8 dB, and the rectifier’s highest RF signal to direct current conversion efficiency is 74.3%. For the combined configuration unit of measure, the antenna is assimilated into the rectifier via back-to-back 50 Ω Sub Miniature Version A (SMA) connectors. The highest recorded efficiency of 49.67% was obtained for the rectenna at optimum values of 1 kΩ resistive load and −5 dBm power input. It has been revealed that the rectifier-integrated antenna presented is effective for low-input RF energy capture and power transmission.

Transformation of reverse marketing model for electrical appliances based on Markov chain optimization with information technology support

Inverters are widely used in the military, industrial production and defense fields as current conversion devices that convert direct current to alternating current. If the inverter fails, it can cause damage to other equipment, resulting in financial losses and, in extreme cases, compromising the safety of users. In this study, by integrating neural networks, the input signals of inverters are quickly converted to Fourier spectrum amplitudes, and from fault signals (such as load phase voltage) to feature vectors. In order to realize automatic extraction and fault detection of inverters, an optimization method is used to determine the appropriate number of nodes in the hidden layer of complex neural networks. The ability to efficiently allocate limited computing, storage, and network resources to meet user demand for services; Continuously optimize quality of service (QoS), including reducing latency, improving bandwidth, and increasing reliability. These problems directly affect the performance and user experience of MEC systems. By studying these issues and proposing corresponding solutions, we aim to improve the performance of MEC systems and provide higher quality services. The accuracy of defect diagnosis can reach higher than 99%, and the method has a high remission rate, demonstrating its effectiveness and benefits.

A review of alternative finishing options for uranium/plutonium and minor actinide nitrate products from thermal and fast reactor fuels reprocessing

In fuel reprocessing, product finishing is the conversion of aqueous metal nitrates into solid forms that can either be re-used in new fuels or safely interim stored and so is the key step at the interface between reprocessing and fuel manufacturing processes. Conversion processes were originally developed for the fabrication of oxide fuels and have typically involved the generation of UO3 (or U3O8) and PuO2 powders as separate products. However, whilst this is an industrial proven process, research and development of mixed oxide (MOX) fuels and minor actinide targets by advanced reprocessing routes is also underway. It is envisaged that advanced recycle processes will allow the multi-recycling of plutonium and the transmutation of minor actinides into shorter lived isotopes to enhance sustainability of the nuclear fuel cycle and fully utilise fissionable material recoverable from spent fuels whilst improving a number of key features over current conversion processes including: product conversion efficiency, higher throughput, flexibility in product specification, proliferation resistance and a reduction in the number of waste streams produced.Internationally, research programmes to examine future options for advanced fuel cycles are focusing on the development of advanced reprocessing flowsheets for future actinide recycling. It is anticipated that these separation processes will produce a range of mixed transuranic (TRU) actinide nitrate products rather than the separated pure plutonium stream produced in current reprocessing plants.The easiest assumption is that these nitrate products will be converted to oxides by the oxalate co-precipitation route. However, this has certain limitations. The focus of this review is to identify any alternative nitrate to oxide conversion processes which have been applied to mixed oxides and evaluate their suitability for MOX production. A variety of factors including process complexity, technical maturity, effluent treatment/recycling and scale up into an industrial process will also be considered.

Molecular engineering of inorganic halide perovskites and HTMs for photovoltaic applications

AbstractA comprehensive study was performed for the design of ABX3 perovskites, (A = Li, K, Na, B = Ge, Sn, Pb, X = F, Cl, Br, I) and organic hole transfer materials, HTMs (Fu‐2a, Fu‐2b, Fu‐2c, and Dm‐Q) for efficient perovskite solar cells (PSCs) through quantum chemistry calculations. Photovoltaic characteristics of the investigated perovskites are strongly affected by the halide anions. The results reveal that reducing the exciton binding energy of perovskites enhances the rate of the formation/dissociation of holes and electrons so F‐based perovskites are superior from this viewpoint. Additionally, the electron and hole injection processes are more favorable in the case of the F‐based perovskites in comparison with other studied perovskites. Moreover, spectroscopic properties of the perovskites demonstrate that KSnCl3, NaSnCl3, and F‐based perovskites exhibit a greater ability of the light‐harvesting and incident photon to current conversion efficiency. Ultimately, based on diverse analyses, F‐based perovskites, KSnCl3 and NaSnCl3 are the preferred candidates to be applied in the PSCs due to an excellent incident photon to current conversion efficiency, light‐harvesting efficiency, short circuit current, and solar cell final efficiency.

Surface oxidized Ti3C2 MXene: Lead-free Cs2AgBiBr6 double perovskite solar cell efficiency enhanced by interfacial engineering

In this study, thermal oxidation method is followed to prepare surface oxidized titanium carbide (TiO2-Ti3C2) nanomaterial. Here, the formation of anatase phase TiO2 nanoparticles over the surfaces of Ti3C2 MXene is confirmed by UV–Vis, FT-IR, XRD and FE-SEM and HR-TEM studies. The TiO2-Ti3C2 MXene acts an interfacial layer in double perovskite solar cell that exhibits high open circuit voltage (Voc of 1.01 V), short circuit current density (Jsc of 2.64 mA/cm−2), fill factor (FF of 0.55) and power conversion efficiency (PCE of 1.35%) under ambient conditions. Hence, we suggest that this surface modified material will be useful for double perovskite photovoltaics applications.

Performance and Impedance of a Partially Flooded Cathode Catalyst Layer in a Low-Platinum Polymer Electrolyte Membrane Fuel Cell

A model for performance and impedance of a partially flooded cathode catalyst layer (CCL) in a low-platinum PEM fuel cell is developed. The CCL is modeled by a system of cylindrical pores approximating real pore–size distribution in the electrode. The model includes oxygen transport along the pores and through the ionomer film covering Pt/C agglomerates. Part of the pore domain adjacent to the membrane is allowed to be flooded. Fitting of the model to experimental impedance spectra of a low-platinum PEM fuel cell shows 30%–40% CCL flooding. Flooding effectively reduces the CCL volume available for current conversion, thereby lowering the limiting current density due to oxygen transport through the ionomer film.

Electrodeposited CZTS loaded titania nanotubes for photocatalytic water splitting

Copper Zinc Tin Sulphide (Cu2ZnSnS4 (CZTS)) is a promising semiconductor material with optimum direct band gap of 1.4-1.6 eV, large light absorption coefficient (> 104 cm-1) and p-type electrical conductivity. In addition, its earth abundant and non-toxic elemental constituents make it a good candidate to replace the CdTe and CIGS absorber layers used in thin film solar cells. Also, it has properties that make it useful as a buffer layer that helps to reduce the effective band gap of TiO2 when used as an anode for photocatalytic splitting of water. We prepared titania nano tube (TNT) arrays by anodization of titanium foil. Raman spectrum of TNT confirmed the presence of pure anatase phase of TiO2. Field emission scanning electron microscopy images were obtained to analyse the surface morphology of TNT. CZTS sensitized titania nano tube arrays were then prepared by the electrodeposition of CZTS thin films over TNT arrays. FESEM images of the CZTS sensitized titania nano tube arrays showed that the electrodeposited CZTS layer had a fibrous structure. A photo electro chemical (PEC) cell was set up with CZTS sensitized titania nanotubes as anode. An anodic current density of 0.19 mA/cm2 was shown by the PEC cell when the anode was irradiated with blue light of wavelength 430 nm at power 50 mW/cm2. The incident photon to current conversion efficiency was 1.1 %.

Revealing the impact of significant improvement in the solar-driven water oxidation of 1-D Co2P2O7 modified BiVO4 photoanode

In this report, we have prepared 1-D Co2P2O7 nanostructures, which works as an efficient oxygen evolution catalyst when loaded over BiVO4 through drop casting followed by annealing procedures. Different structural, morphological, elemental and optical analysis confirms the deposition of Co2P2O7 over BiVO4. The optimum loading of Co2P2O7 shows, 4.5 times higher value of the photocurrent densities than pristine BiVO4 photoanode in the 0.5 M of Na2SO4 electrolyte. Apart from this, the oxygen vacancies within the BiVO4 /Co2P2O7 structure have been increased due to the loading of Co2P2O7 over BiVO4. Well optimized BiVO4 /Co2P2O7 photoanode shows:- (i) drastic cathodic shift in the initial potential of the oxygen evolution analyzed by Butler plot, (ii) incident photon to current conversion enhanced by 4.6 times, (iii) Mott-Schottky analysis shows shifting in the flat band with very high donor density, (iv) high charge injection efficiency improved by 3 times and (v) exceptional photostability. At the end in depth photoelectrochemical impedance spectroscopic studies have also been done to understand the influence of loading of 1D-Co2P2O7 over BiVO4. The outcomes of this research open the way for a simple plan to achieve the ideal co-catalyst/semiconductor coupling necessary for effective solar fuels manufacturing.